Fuel burning apparatus



y 1936- E. H. CARRUTHERS ET AL 2,048,321

FUEL BURNING APPARATUS Filed June 8, 1933 2 Sheets-Sheet l AY KM ATTORNEY July 21, 1936.

E. H. CARRUTHERS ET AL FUEL BURNING APPARATUS Filed June a, 1955 2 Sheets-Sheet 2 ATTORNEY Patented July 21, 1936 eaten PATENT OFFICE FUEL BURNING APPARATUS Eben H. Carruthers and Dana B. Green,

Ithaca, N. Y.

Application Juliet, 1933, Serial No. masts 10 Claims.

This invention pertains to the art of combus-- tion controls, and more particularly relates to an improved burner hood capable of handling gaseous fuels or the like combustibles, and further relates to associated appurtenances adapted to thoroughly atomize and efliciently burn the heavier grades of liquid fuel in either small or large sized units for use in new or existing household heaters, boilers or the like furnace devices.

In the present system, such atomized liquid fuel is preferably burned in a stepwise or multizone manner, being initially mixed with a. re stricted, minor body of primary air that in itself is insufiiclentto support complete combustion but adequate to vaporize all such fuel into a preheated oil-gas state or the like combustible. Our I burner may be provided with a horizontally disposed hood preferably having a cross-sectionally crowned shape that is radially slitted or otherwise 20 given a plurality of similar jet apertures therethrough, and which jet slits are placed in a crosswise relation to a centralized upturned atomizing nozzle. This nozzle is preferably encased in venturi fashion within the contracted end of a flared tubular housing and the enlarged upturned end of which housing is bridged by the aforesaid hood member. The partially burned oil-gas while flowing upwardly through said housing, is allowed to expand laterally for distribution through the various jet apertures, whereupon said oil-gas or combustible is additionally mixed with a major portion of supplementary air that completes combustion of such oil-gas immediately upon its being ejected from the respective hood slits.

For present purposes, the well known jet suction principle, is applied in an improved manner to produce a novel result in flame distribution over the whole of the upturned or upper hood surface. The supplementary air quota required to complete combustion of the oil-gas is preferabl'y fed radially inward from the hood perimeter toward its embraced center region in order to effect a well distributed, short flame formation. To this end, our crowned hood surface may be channelled with one or more crossfeed conduits that are respectively interposed between certain of our jet slits; the bottom confines of each such channel is preferably kept depressed or sunken with respect to the aforesaid hood surface in an upwardly inclined relation to the contiguous jet discharge edges that lie to each channel side, so as to bring the delivery of said conduit into the intended cooperative feed relationship with the ejected oil-gas.

A preheated supply of supplementary air may be fed upwardly around the hood perimeter and into the respective outermost conduit ends. The vacuum influence created along the contracted nozzle zone of each such oil-gas jet is utilized to 5 suck supplementary air radially inward and lengthwise of the several upwardly sloping conduits toward the raised apex of our hood. Certain localized hood regions including the burner center are thereby fed by an independently l0 conveyed air stream rather than being obliged to indiscriminately pick up the required air quota from the surrounding atmosphere.

Such final crossfeeding of air into the burner flame serves to thoroughly mix the constituents 15 and to automatically fix in a fairly definite and maintained proportion, the ratio of oil-gas to the air needed to complete its combustion, particularly so as applied to burners of relatively large capacity. The issuing fuel may thereby be burned throughout the length of our jet slits with the minimum quota of air consistent with perfect combustion; the resulting high flame temperature promotes efliciency and tends to eliminate the. formation of flue soot.

In order to attain a steady and noiseless initial combustion of liquid fuel in the atomizing nozzle region, inert or the like spent flue gases, may be continuously introduced in the vicinity of the injected fuel spray to bring about a more gradual 0 or retarded rate of combustion on part of the primary air mixture that shall be free from flutter.

The object of our invention is to devise an improved burner of the character indicated and to construct the necessary instrumentalities with which to carry out the cited underlying principles of operation including a tubular shell within whose confines the combustion chamber is neatly encased in unitary fashion, all of which features 4 will behereinafter more explicitly set forth.

As a'primary purpose, it is emphasized that each crossfeed hood channel is herein so arranged that a supply of fresh air when introduced into the outer channel end, may be conveyed inwardly along said channel toward the medial region of our burner hood and which air is kept segregated for delivery in its initial state of purity to one or more jet apertures without flow interference or pollution by spent products of combustion that may simultaneously issue from other contiguous jets, until all of such conveyed fresh air has been sucked into and mixed with the combustible that is being ejected through the respective jet apertures served by said channel. By the use of a plurality of radial slits or equivalent rows of jet apertures when fed by such crossfeed conduit 'means, we are enabled to efliciently distribute a Jflame over-a hood surface of wide extent and still maintain a virtually identical mixture proportion between the ejected gaseous combustible and its proper quota of air along the entire length of the respective slits or jet rows and which mixture can be made to burn with substantially the same relative short blue flame characteristic in both the inner and outersurface regions of our hood.

Reference is had to the accompanying two sheets of drawings which are illustrative of several alternative embodiments of our invention,

and in which drawings:

Fig. 1 is an upright perspective view of a conventional household boiler or the likefurnace assembiy of which its jacket is partially broken away to show our oil burner equipment installed therein.

Fig. 2 represents a top view of our preferred style of burner devices as seen from line 2-- of Fig. 1 but as removed from the boiler jacket, while Fig. 3 depicts an elevational cross-section taken along the offset line 33 of Fig. 2 to schemati cross-section thereof as taken along line 8-8.

Referring first to Figs. 1 to 3, I 0 denotes a water jacket of an upright boiler or the like heating furnace adapted to have our fuel burner system installed therein. .Said burner may comprise a box shaped, compartmental base casting II that isshown provided with a U-shaped, supplementary air duct enclosure i2. In its yoke end region, the top wall of this duct is kept open as cross-sectionally detailed in Fig. 3 while the respective perimetrically complete leg end walls of this duct may beextended forwardly through the ash pit door of a boiler as indicated. Interposed between such duct legs, is a nozzle duct H of which the forward end may be sealed by an apertured cover plate l5 while the rearmost duct end discharges upwardly throu h a contracted neck 'or Venturi port l5 as sho n, it being the intent to so encase said nozzle duct N that it shall be kept separated and reasonably airtight with respect to the adjacent base duct I2. Either .or both of said ducts may be equipped with adjustable throttle means such as l3 serving to regulate the flow therethrough.

Resting concentrically about said circular port I 6, is the contracted end of a flared tubular liousmg I I serving to form a primary combustion chamber I8 therein. This upright housing may be cast of iron and have the upturned mouthminates in a spray nozzle 24, said nozzle being upturned in axial alignment with the flared housing I I and its Venturi port I 6.

Such centralized nozzle is preferably served by a controllable fuel pump (not shown) of any suitable motor driven type adapted to thoroughly atomize liquid fuel and thereby project a spray upwardly from the Venturi port in the diverging manner indicated in Fig. 3. This spray is intended to be sufliciently powerful to give the required impetus to the surrounding gaseous medium so as to create a slight pressure head in'the uppermost or hood region of the combustion chamber I8; also to suck the desired amount of primary air'i'nto said combustion chamber out of 15 the air passage 22 through the inspiratorport l9, the latter being placed under the influence of the slight vacuum that is created by the ejected fuel oil in the lowermost nozzle region of our combustion chamber.

within limits that will merely promote incomplete combustion of the sprayed fuel and thereby form an unsatisfied oil-gas mixture needing an, addi- Said lnspirator port is 20 definitely sized to restrict the resulting air flow tional air quota to complete its combustion. The 25 air content that is allowed to initially mix with-1, the atomized fuel, may be reduced by raising and thereby placing the inspirator port iii in amore femote position with respect to the intensified suction zone of the nozzle 24.

Our apertured burner wall or hood shaped crown piece 25 is transversely superimposed to span the flared end of the upstanding housing i1, and may be given a cross-sectionally blunt cone shape or equivalent profile of which the apex is 35 preferably kept elevated in relation to the hood perimeter. Such crowned burner wall may either be cast solid or built upfrom a plurality of separable and independently expansible hood sectors such as 26 of which the respective mated radial faces are assembled to constitute a circular formation of the kind shown in Fig. 2. These various hood components may be bolted together as at 21 into a unitary assembly having, a relatively small imperforate central region from which the several sector sidefaces radiate. As detailed in Fig. 7, it is preferred to laterally inset the medial region of each such sector sideface relative to the respective terminal regions thereof so as to provide for a narrow burner slit 28 or the equivalent jet aperture between each consecutive pair of assembled hood sectors.

As disclosed in Figs. 7 and 8, the cross-sectional profile of each hood sector is purposely given a troughlike shape to form an upwardly sloping crossfeed channel or conduit 29 as interposed between adja ent burner slits and of which channel, the bott inmost confines or wall element 88. is kept vertically depressed in an inclined cooperative feed relationship with respect to the 60 topmost discharge edges of such adjacent slits. It is preferred to make the upward inclination of the wall 38 steeper than the corresponding slope given to the contiguous discharge edges in order to'aiford a gradually rising air flow toward the 65 hood apex that shall uniformly feed the asso It will be obvious that such built-up hood sectors may also be given a flat top formation in the manner of the Fig. 5 disclosure.

At the perimetric region of our hood, theen larged intake end of the respective crossfeed conduits may be directed downwardly around the flared housing I! as in Fig. 3-and placed in direct communication with the annular passageway 22 ciated hood slits throughout the length thereof.

through the air feed ports such as 3|. when resorting to an integral burner hood, the upturned surface thereof'would likewise be formed with a series of radially disposed jet apertures that similarly have a crossfeed channel 29 interposed and sunk between the respective consecutive jet apertures. The hood perimeter is shown centered within the shell 2i.

As a further structural refinement, we may.

resort tothe downcomer pipe 32 whose bottom flange may be demountably-upheld by the top plate of the base casting I I, said plate being apertured to allow said pipe to unobstructedly deliver into the.encased nozzle duct it. As shown in Fig. 3, the uppermost pipe end may be pro-' vided with a mouth piece 33 that spacedly overhangs certainof the hood slits and whose intake area is suitably proportioned to admit the desired quantity of spent combustion products.

The mode of operation of the described appurtenances may be traced as follows: It may here be pointed out that when applied to furnace purposes, our burner is preferably actuated intermittently, that is-to say the burner flame is either kept full on or shut down completely to suit prevailing heating needs; To this end; the midregion of our housing wall may have a primary electric igniter 34 or equivalent pilot flame inserted therethrough to light the atomized fuel oil from the instant that the nozzle 28 starts to spray.

The associated control equipmen't may be of the conventional kind (not shown) serving to automatically stop the fuel pump delivery in the event that the sprayed fuel should fail to ignite promptly or when the boiler pressure rises abnormally. Suitable thermostatic means may also be employed to conunand the motor driven fuel pump and thereby render the installation self regulating; on the other hand, the nozzle delivery may in certain instances, be manually varied to'suit certain special requirements. As a further safeguard against failure to light the sprayed fuel mixture, we additionally provide for a secondary igniter 35 or equivalent pilot flame supported by the shell 2! as disposed exteriorly of the primary.

combustion chamber I8 in a contiguous relation to one of the several hood slits (see Fig. 3).

Assuming fuel oil to be supplied under pressure into the line 23 and that this is initially sprayed through the nozzle 24, the effect will be to create a partial vacuum in the vicinity of the Ventm'itube It. The open ended base duct 12 takes in atmospheric air of which a limited portion is passed through the admission feed port 19 and into the combustion chamber l8. As soon as a burnable mixture is formed therein, the igniter 3t lights this mixture to initiate incomplete combustion on part of the entered charge; the spreading hot burned products then rise upwardly and are distributed through the burner slits 28-, whereupon the combustion of the ejected oil-gas is completed exteriorly of the primary chamber It. The supplementary air lying within the passageway 22 will thereupon become preheated by contact with the relatively hot housing wall l1 and which air rises vertically through the various perimetric hood ports 3| that respectively lead into the enlarged ends of the sector crossfeed conduits 29. The intended flow path of the different fluid bodies may be traced by the arrows of Fi 3.

As will be understood, the partially burned oilgas when ejected through the various'radial hood" slits, creates a slight vacuum along each of the slit discharge edges, which in turn is utilized set to suck all of the supplementaryair radially inward and risingly along its upwardly inclined sector or bottom plate 30 of the crossfeed conduit 29 in a proportionate relation to the oilgas flow. The cited jet suction actionimpar'ts mobility to the supplementary air being conveyed along such a channel and ultimately draws amount of such air over a longer feed distancei',

it is the intent to so shape and proportion eachsloping crossfeed conduit that a substantially uniform flame characteristic will be attained along the whole length of the various slit jets.

As a result, we are enabled to build our updraft" burner in sizes possessing a relatively large heat ing capacityand still utilize substantially all of the crowned space lying within the perimetric confines of our hood as served.

As regards the function of the downcomer 32, the overhanging mouth thereof serves to =by-- pass spent flue gases from above the burner for delivery through the nozzle duct It, whence it is conveyed into the primary combustion chamber. A relatively small proportion of such diluent or inert products of combustion, tends to deaden the intensity and effectively retard the initial rate of combustion on part of the finely atomized fuel oil and thereby eliminate hissing or the like noisy flame disturbances that are frequently enco'untered in-fuel oil burners of larger capacity.

Referring now to the modified burner structure disclosed in Figs. 4 and 5, this may comprise a base casting 40 essentially similar to that used in Fig. 3 except for the downcomer pipe '32. Mounted upon said base is a flared chamber housing 4| of which the contracted Venturi tube region is'embraced by an annular header passage 7 42 having one or more radially disposed feed ports 43. Said header is here'independently supplied with spent 'products of combustion or the like inert fluegases through the intake pipe 44 from any source.

The base casting 40 may likewise be equipt with an air duct 45 and a nozzle duct 46. The atomizer nozzle 41 is again disposed at the converging region of the flared combustion chamber and directed to unobstructedly discharge upwardly toward the hood as shown. Said nozzle is distinguished Yn type over the previously described nozzle 24 in that the air required for primary fuel combustion may here be injected through said atomizer nozzle 41', in which event the air and liquid fuel supplies may be separately conducted thereto by. the use of concentrically disposed feed pipes respectively designated 47A and 41B and which are similar to those that have been more fully illustrated in Fig. 3. Such practice in turn; eliminates'the need for any admission air feed ports in association with the flared housing ll of Fig. 5. It will also be observed that the contracted end of the flared combustion chamber snugly surrounds the divergent spray formation and places the ports #3 within sucking influence of the nozzle zone. In addition,

wardly and thereby insure a substantially uniform distribution through all of the hood jets.

In this alternative structure, the upturned top face of the one piece hoodwall 48 is 'shown as flat and provided with a series of radially disposed jet apertures 49 which may here be carried diametrically across the hood center. Between each such group of alignedjets, our hood wall is again channeled and shaped to provide for a relatively depressed and upwardly inclined bottom wall element 50. In lieu of acylindrical burner shell, the furnace jacket is equipt with an annular partition plate 52 whose interior Y some of the more remote jets may fail to suck I to themselves, the required full quota of supplementary air. If desired, said vane may also be carried by a burner shell 54 in the manner represented by dotted and dashed outline in Fig. 5. As regards the underlying mode of operation of the last described burner assembly, this is basical- 1y analogous to the Fig. 3 showing.

It'remains to point out that our updraft burner hood may take on various forms,- of which still another structural modification is exemplified in Figs.- 6 andfiA. This disclosure is diiferentiated over the Fig. 3 style of burner in that the perimeter of the upper hood surface 55 is here provided with a depending skirt portion 55A. A single continuous jet slit 56 is so arranged that ohe end region thereof is made to pierce said skirt while the opposite slit end is disposed topierce the sloping upper hood surface 55. A series of such angularly shaped slits may be symmetrically disposed about the hood center region as shown to distribute a short flame over substantially the whole of the upper surface and also downwardly 1 along the pierced skirt portion. A separate crossfeed conduit maybe interposed between each pair of next adjacent slits and each iiiiclined bottom wall 51 of this particular style of conduit preferably extends from the lowermost pierced skirt edge region to feed upwardly toward the raised crown region of suchhood. The hood perimeter may further be equipped with radially disposed fins 58 adapted to be centered within the circumscribing shell 59 and still allow for an unhampered flame formation along each depending component of the slit 56. Equivalent results may be obtained by the use of individual jet holes of the kind shown in Fig. 4. For certain purposes, the shell centering portion of the fin Bil-that projects beyond the hood perimeter, may be dis-- tion, it being emphasized that the cited crossfeed hood feature may be also eflectively applied to the handling of fixed gaseous fuels or other combustible vapors even-shouldthese be ignited and burned-in unizone fashion subsequent to their being discharged through our intersecting nest of improved hood-slits. It is to be understood that various other changes in the structural details and organization thereof may be aoaassi the opposite end region of said chamber and 10 which hood includes jet outlet means, a supply of liquid fuel, atomizer nozzle means directed toward the'hood and arranged to unobstructedly deliver said fuel through said Venturi tube, and a supply of air of which a restricted portion is introduced into said chamber to partially burn the atomized fuel into a combustible mixture that is thereupon ,ejected outwardly through the jet outlet means and another portion of which air is added exteriorly of said chamber to complete the combustion of the ejected-mixture whereby the constituents of the resulting combustion products are maintained in a substantially, uniform ratio throughout the burned mixture.

' 2. In a burner of the multizone type, the combination of a tubular combustion chamber of which one end region is contracted to constitute Venturi tube means, a hood bridgingly enclosing the opposite end region of said chamber and which hood is provided with a plurality of jet outlets, a supply of liquid fuel, atomizer nozzle means directed toward the hood and arranged to unobstructedly deliver said fuel through said Venturi tube, a supply of air of which a'restrioted portion is introduced into the combustion chamber to partially burnthe atomized fuel into a combustible mixture that is thereupon ejected .outwardly through the several jet outlets and analternate channels and ridges, each such ridge being provided with an elongated jet slit ex-' tending radially toward the center region of said surface and which channels are respectively in- -terposed therebetween to extend inwardly from the border of said hood, a supply of liquid fuel, atomizer nozzle means directed toward the hood and arranged to unobstructedly deliver said fuel upwardly through said Venturi tube, and a supply of air of which a restricted portion is introduced into said chamber to partially burn the atomized fuel into a combustible mixture that is thereupon ejected outwardly through the several jet slits and another portion of which air is introduced into the border end of the respective hood channels and conveyed therealong to complete the combustion of the eiected'mixture, the constituents of the resulting combustion products being maintained in a substantially uniform ratio throughout the length of each such elongated jet, si 4. In a burner of the multizone type, the combination of a tubular combustion chamber of which one end region is contracted to constitute Venturi tube means, a built-up hood assembly spanning the opposite end region of said chamber and which hood comprises a plurality of component sectors each including complementary radial side faces of which a medial face portion is kept spaced apart from their respective next adjacent side faces to provide for a jet slit therebetween and which component sectors each have. an air conveying channel located between the the hood channels to complete the combustion of the ejected mixture.

5. In an updraft burner of the multizone type, the combination of an upstanding tubular combustion chamber of which the lower end region is contracted to constitute Venturi tube means, a hood bridging the opposite end region of said chamber and which hood is provided with an exterior upper surface shaped to form alternate channels and ridges having a skirt portion that depends from the hood perimeter, each such ridge and a contiguous skirt portion being pierced by a jet aperture and which channels are respectively interposed therebetween, a supply of liquid fuel, atomizer nozzle means directed toward the hood and arranged to unobstructedly deliver fuel upwardly through said Venturi tube, and a supply of air of which a restricted portion is introduced into said chamber to partially burn the atomized fuel into a combustible mixture that is thereupon ejected through the several jet apertures and another portion of which air is introduced into the respective hood channels and conveyed therealong to complete the combustion of the ejected mixture.

6. In a burner of the multizone type, the combination of a tubular combustion chamber of which one end region is provided with Venturi tube means, a hood spanning the opposite end region of said chamber and which hood includes jet outlet means, a supply of liquid fuel, atomizer nozzle means directed toward the hgod and delivering fuel into said tube means, feed port means admitting into the combustion chamber and which means are located intermediate said tube and the hood, and a supply of air of which a restricted portion is introduced through said feed port means to partially burn the atomized fuel into a combustible mixture that is thereupon ejected outwardly through the jet outlet means and another portion of which air is added exteriorly of said chamber to complete the combustion of the ejected mixture.

7. In a burner of the multizone type, the combination of a vertically disposed annular shell provided with a bottom closure and having an air inlet opening, a flared tubiform combustion chamber erected endwise within said shell hav-- ing the convergent chamber end disposed contiguous to said bottom closure and providing for chamber ends and placing the chamber interior in direct communication with said passageway,

a hood spanning the divergent upper chamber end and which hood includes jet outlet means,

a supply of liquid fuel, atomizer nozzle means 5 directed toward the hood and delivering fuel into the convergent chamber end, and a supply of air conveyed along said passageway and of which air a restricted portion is introduced through the feed port means to partially burn the atomized fuel into a combustible mixture that is thereupon ejected outwardly through the jet outlet means and another portion of which air is added exteriorly of said chamber to complete the combustion of the ejected mixture.

8. In a burner of the multizone type, the combination of a tubular combustion chamber of which one end region is shaped to provide for Venturi tube means, admission feed port means located intermediate the respective chamber ends, a hood 20 spanning the opposite end region of said chamber and which hood includes jet outlet means,

a supply of liquid fuel, fuel atomizer means delivering into the Venturi tube, a shell embracing said combustion chamber and forming a 25 passageway therebetween which communicates with the jet outlet means, and a supply of air that is introduced into said passageway and conveyed to the jet outlet means through the afore- 'said communication and the feed port means.

9. In a burner of the multizone type, the combination of a tubular combustion chamber of which an end is provided with Venturi tube means, a hood spanning the opposite end region of said chamber and which hood is provided with 35 a transverse exterior surface shaped to form alternate channels and ridges, each such ridge being provided with a jet aperture and which channels are respectively interposed therebetween to extend inwardly from the border of said hood, outstanding fins disposed radially of said hood to partition medially said channels, a supply of liquid fuel, atomizer nozzle means arranged to deliver fuel into said Venturi tube, and a supply of air of which a restricted portion is introduced into said chamber to burn the atomized fuel into a combustible mixture that is thereupon ejected outwardly through the jet outlet means and another portion of which air is added exteriorly of said chamber to complete the combustion of the ejected mixture.

10. In an updraft burner of the multizone type, the combination of an upright tubular combustion chamber of which the lower end region is contracted to constitute Venturi tube means, a hood bridgingly enclosing the upper end region of the chamber and which hood includes jet outlet means, a supply of liquid fuel, atomizer nozzle means directed upwardly toward the hood and arranged to unobstructedly deliver said fuel 60 through said Venturi tube, and a supply of air of which a restricted portion is introduced into said chamber through the Venturi tube to partially burn the atomized fuel into a combustible mixture that is thereupon ejected outwardly 5 through the jet outlet means and another portion of which air is added exteriorly of said chamber to complete the combustion of the ejected mixture, the upper end region of said chamber being kept at a relatively higher pressure than 7 prevails in the lower end region thereof.

EBEN H. CARRU'I'HERS. DANA B. GREEN. 

